It's okay dude. We all get urges. Don't feel like you've failed because you can't resist the temptation to do it. Sometimes I do it and go why the hell did I just do that? I'm trying to do it less and you should to. Hopefully you can to and we can both ease out of it.

Well if pain is really what you want, might as well do it right, right? So why not just put some salt on the wound, it disinfects and stings quite a bit. This way you don't risk damaging your tissue so much or any deep cuts that may render your muscle tissue/nerves useless.